Production of solvents



Jilly 26, 1960 VI RGIN mum;

H. E. BLOOMSBURG ETAL PRODUCTION OF SOLVENTS Filed Oct. 15, 1958 SULFUR DIOXIDE *DISTILLATION ZONE SOLVENT STRIPPEN ZONE .a-SOLVENT EXTRACTION ,/SOLVENT STRIPPE R swss'rsmue ZONE IMPROVED ODOR SOLVENT INVENTORS U e sates Patfi The present invention is directed to a method forimproving'the odor of solvents. More particularly, the inhydrocarbon fraction containing aromatic and saturated hydrocarbons and odoriferous compounds boilingin the range from about 100 to about 450 F. is subjected to solvent extraction to form a rafiinate phase and aniextract phase. The rafiinate and extract phases are freed of solvent and the solvent-free extractphase is then distilled to reject light and heavyarornatic compounds and the odo'riferous compounds contained therein to obtain a he'artcut fraction distilling between about 40 percentand about 90 percent of the extract phase. The heart out traction and the rafiinate phase may be sweetenedor hydrofined after combination or prior to combination, as may be desired.

The solvent employed in the practice of the present invention is preferably sulfur dioxide and may be used at temperatures in the range from about to -60 F. A solvent-to-hydrocarbon ratio of about'SO to 200 may be employed in the present invention. Other selective solvents may be used, such as ph'enol,-diethylene glycol, furfural, or adsorbents such as silica gel, and the like may beused.

The hydrocarbon fraction is preferably a hydrocarbon obtained from crude petroleum and may boil in the range from about 100 to about 450 F. andusually boils in the gasoline boiling range. Fractions boiling in. the kerosene range may also be employed. This hydrocarbon fraction contains saturated hydrocarbons and} aromatic hydrocarbons, as well as odor-iferous compounds which may be aromatic-type compounds.

It has been discovered that the odoriferous compounds are concentrated in the 0 to- 40 percent fraction of the extract phase and the'90 to 100 percent fraction'of the extract phase. This is indeed surprising since ordinarily it would be expected that odor-forming or odoriferous compounds in fractions of this'nature would normally be concentrated only in the heavier fractions. By virtue of this discovery, it is now possible to improve the odor of solvents by selectivelyrejecting the aromatic hydrocarbons which contain the odoraforming or odoriferous compounds.

It is desirable to sweeten the raifinate'aud fractions of the extract phase and this may either be done separately Engineering Company, Elizabeth,"N.J., a corporation with the saturated constituents of the" erence'to the drawing whic is a flow diagram'of the preferred method. I

Referring nowto the'drawingnur'neral ll-desi-gnatesa charge line by way of which a virgin naphthais introduced into distillation zone 12 which is shown as a single fdistillation tower but which may be a plurality of distillation towers. In any event, distillation zone 12 is provided with suitable vapor-liquid contacting means, means for inducing-refluxand auxiliary condensing and cooling means usually associated with amod'er'n' distillation tower. Zone 12 is shown as being provided with a heating means illustrated by steam coil '13 which is employed to adiust -temperatures and pressures. Zone 12 is operated to obtain, by way of line'14, a: fraction boiling in the range from about 100 to about 45 05F. which is introduced by line "14 into a solvent extraction fzone 1 5. Heavier fractions are discharged from'the zone 12 by line 16 for further use as maybe desired.

The'solvent naphtha fraction introduced into zone :15 by line 14 contacts countercurrently a solvent such as sulfur dioxide introduced into zone 15 by line 17.- It is understood, of course, that zone15 is provided'with internal liquid-liquid contacting means 'to provide intimate contact between the liquid solvent and the hydrocarbon. Under the conditions oftemperature and solvent-to-hydrocarbon ratios mentioned before, an extract phase and a ,ratfinatephase are formed in zone 15, the ralfina-te phase being withdrawn by line-18 while the extract phase is discharged 'by line 19.- The raflinate phase is introduced into a solvent stripper 20-provided with a heating means such as, steam coil, 21 for removal of solvent by line 22 from the ralfinate phase, the raflinate phase free of solvent discharging from stripper 20 by line 23.

'Iheextract phase in line 19 is likewise introduced into a solvent stripper 24 provided with a heating means such as 25 to cause removal of the solvent from stripper 24 by line 26 and to allow the withdrawal of a solvent-free extract by way of line 27. t

The solvent-free extract is introduced by line 27 into a distillation zone 28 which is similar to distillation zone 12 being provided with all auxiliary equipment for performing its necessary function. Zone 28 is provided with a heating meanssuch as steam coil 29 for adjustmentof temperatures and pressures. By proper control of temperatures and pressures, a light fraction is removed from 'zone 28 byline 30 which may comprise from O to 40 percent of the extract introduced 'by line 27, while a heavier fractionf comprised of to percent of the extract is withdrawn by line 31. A heart out fraction is withdrawn from zone 28, which may comprise 40 to 90 percent of the extract, by Way of line 32.

It'is to be noted that'a line 33 controlled by a valve 34 is provided and this is to allow the obtaining of heart cut fractions of varying width. For example, it may be desirable to obtain a 50 to 90 percent heart cut fraction or a 60 to 90 percent heart cut fraction. In that event, a 0 to 50 percent or a 0 to 60 percent fraction might be obtained byline 32 or selected fractious might be obtained by line 32 and'the desiredfraction byline 33. In any event, line 32 and. line 23 are controlled, respectively, by valves 35 and 36 and they two lines connect and merge'into line 37. to allow combining or'blending of the r'affinatepha se in any desired proportion. The comhaving kauributanol values within the range from about 35 to about 40 are obtainable in the present invention.

It ,may be desirable to sweeten the rafiinate phase and t e tra ion o th ext ac ph sesep y d t hi end, either valve 35 or valve 36 may be closed, depending on which fraction is to -zbe sweetened first, with the other in ct n bein stored i s orage {tank (no show prior to its separate sweetening.

It is also co template {that th tw erect ons may lended in the ra o 9f th ex ract pha o h .r fii a e ph se such that a solvento improved odor an so v ncy alu :i {obtaine zBy ble din he sele ed heart m raction f .the extract .ph se and the ra a rhas i theretioofth xtrac rt raflin t a solven of mprov olvency a up as obtained. it is :t h un e sto d ha an b en tam v be made to a selected s lvency .valll ordina ily and p eferablvnotllessrthan thes lven y value ofgthe fraetionisubiected-to solventextraction.

The invention will be further illustratedby reference torthe sfollowingirun "wherein a hydroc rbo e gna e asllarso No. -1 and boilinginzthehrange from about 300 to .460 .F. tWEiS-fihbjfititfid ,under solvent extraction conditions ito "extraction with sulfur dioxide at a temperature of -l to 30 F. The extractphase free -ofsolvent was ether: rfractionall-y, distilled to. obtain :various fractions of ;the extract phase which were ;then,combined .inthe ratio. of; the. extract ;to rraffinategto. ,obtainsolvents ot varying Lodor yratings. 'FIEhe :resnltsof itheseoperatiqns are presented ;in. thezfollowing table.

fIab le I Composition:

-Vars0l No.1,-1 ercent Itafidnate Pereqent 60-90% Extract )3 cti'on, Percen 50-90 7,, Extract F etion,-Percsnt a r %1E?;t F YEQ H; eircent Inspections:

It will be noted that the odor-rating of the Varsol N0. 1 is. substantiallygreater. than the odor rating of the several biendsswith the 60.to .90 percent extract fractiongiving the most desirable result. It is to be further ,noted that the practice of the present invention provides a solvent of increased aromaticity and of appreciated kauri butanol value which is .a, rneasure of the solvency value. of the solvent- In other .words, the .practice of the presentinvent ion not only improved th'e bulk odor of the solvent but .also improved the. s olvency .value thereof.

In accordancecwithrthe presentinvention, the odor of solvents .is improved by. solvent. extracting the aromatics from. a hydrocarbon traction of the desiredboiling range andthendistilling theIeXtIaCted aromatics toreject the lighter. aromatic hydrocarbons for inse as may be desired such-as ingasoline whilethearomatic hydrocarbonscomprising from about 40;to,ahout 90 percent of the solvent extract are a dded to the ,solvent raflinate to provide a solvent of .the lesired. solvency requirement-and of; improved ofdor, the ,aromatic. odor impact of the finished solvent beinglimproved.

in. the present invention the desirable aromatics are concentrated;..ar d .employed in the finishedsolvent providingdesirable.properties -..ther eto. For example, when used in paints, the' paint film,.is, conditioned ondrying since.thefirstftactions.whichevaporate. may be fractions ,of.low er solvency whereas the, remaining ffractionsmay 'be of highers lvency. ,Solvents prepared inaccordance with the present invention; are .theref oreruseiulin paints P o id ng tontin tye vell r andadfienc -the paint or varnishefilrn. f 1

:15 urthermore, .the present invention allows production of solvents-pf -v ,and selected, quality 1 as may be r qui d- :Ih l 91"; 1 ;.9 ?3 i1$ l b %410 --Ya .1 d s edn'athis mavs'b c mp e b addin th selected:aromatics fractionatoy the solvent. raflinate; in an .amonnt twithinsthe .rrange.=-ifrom -about r8 percent; to, about 12 percent by volume to provide the desired characteristics to the solvent and impart to the paint the qualities required. Of course, such a solvent will be of improved odor. Likewise, to obtain a higher kauri butanol value solvent, amounts of the selected aromatic fraction within the range from about 16 percent or 18 percent by volume may be added to the winners. In short, in accordance with the present invention, solvents of any desired solvenc y' value and of improved odor are obtainable by adding the'selectedarorn ics to the solvent raflinate in suhicient amountsito provide a solvent havin'gTa liauri butanol value in the ra Qfrom about to about The present invention 18 therefore of importance and utility. V

The nature .and objects ofthe present invention having been completely described and illustrated, what we wish to claim as new" and useful a'ridto" secure by Letters Patent is:

1. A method forimproving the odor of solvents which comprises solvent extracting a ihYdIOCflI'bOIl fraction boiling in the gasolineand ,kerosene range containing aromatic and saturated hydrocarbons and odoriferous compounds to :form a rafiinate .phaseand an extract phase, separtely removing .and recovering solvent from said phases, sdistilling .thesolvenL-fre'e extract phase to separate and recover a heart out fraction including aromatic hydrocarbons distilling between .about t40% and about 90. pf said .extractphase and to separate and reject odoriferous compounds, .andthen combining said heart out ,fractionwith saidraffinate phase whereby asolvent of improved .odor and solvency value is obtained, .said heart .cut fraction .and said .rafiinate .phase being sweetened. after. separation. and recovery of said heart cut fraction from said solvent-free extract phase by distillation.

. 2. .Arnethodfor improving the odor of solvents which comprises solvent extracting a hydrocarbon fraction containing aromaticnnd saturated hydrocarbons-and 'odori- 'ferous .compoundsboilihg in-therange from about 100 to .abont 450" F. to form a raffinate phase and an extract phase, separately removing and recovering solvent 'fromsaid phases, distilling the-solvent free extractphase to separate and recover a heart out I fraction including varomatichydrocarbonsdistillingbetween about 40% and .:about.90% of said extract phase and to separate and rejectodoriferous compounds, and then-combining said heart vcutlfraction with said raflinate phase in" the ratio ofextraotto r'afiinatecwhereby a solvent of improved odor and solvency value is obtained, said heart Cl1t "fl'3Ci;lbl1 'andsaid rafiinate phase being sweetened after separation and.recov er.yof said heart ciitfra'ction-frorn said solventfreeextract phase by distillation.

3. Amethodin accordancewith claim '2 in which. the heart cut fractio n and raffinate phase are sweetened after combination. 1

-'4. A method in accordance with claim 2 in which the heart out fraction and rafiinate phase are sweetened separately prior to combination. U

5. A "method-for improving the odor of solvents which comprises solvent extracting "a hydrocarbon fraction conta-ining aromatioand saturated hydrocarbons and odor'iferous compounds boiling in the range from about- 100 to about 450 "-F. with'sulfur dioxide ;to fform'a raili'nate phase and an extract phase, separately removing 1d recovering sulfur dioxide-from said phases, distilling sulfur dioxideefree extract phase 1 to separate and recover a h eart cut fraction including aromatic hydrocarbons .distfll nsh twe ab ut 1% an ab u 90I%0f s .extta trhasee d. sena a e a reie er om- A metho .0 im rovin t eodoro sqlv a sgvbisl phase, separately removing and recovering solvent from 6 said phases, distilling the solvent-free extract phase to separate and recover a heart out fraction including aromatic hydrocarbons distilling betweenwabout 60% and about 90% of said extract phase and to separate and reject odoriferous compounds, then combining said heart 10 r 2,731,506

cut fraction with said raflinate phase in the ratio of extract to raflinate, and sweetening said combined heart cut fraction and raflinate phase whereby a solvent of improved odor and solvency value is obtained.

References Cited in the file of this patent UNITED STATES PATENTS Millikan Nov. 22, 1955 Love et al. Jan. 17, 1956 

1. A METHOD FOR IMPROVING THE ODOR OF SOLVENTS WHICH COMPRISES SOLVENT EXTRACTING A HYDROCARBON FRACTION BOILING IN THE GASOLINE AND KEROSENE RANGE CONTAINING AROMATIC AND SATURATED HYDROCARBONS AND ODORIFEROUS COMPOUNDS OF FORM A RAFFINATE PHASE AND AN EXTRACT PHASE, SEPARATELY REMOVING AND RECOVERING SOLVENT FROM SAID PHASE, DISTILLING THE SOLVENT-FREE EXTRACT PHASE TO SEPARATE AND RECOVER A HEART CUT FRACTION INCLUDING AROMATIC HYDROCARBONS DISTILLING BETWEEN ABOUT 40% AND ABOUT 90% OF SAID EXTRACT PHASE AND TO SEPARATE AND REJECT ODORIFEROUS COMPOUNDS, AND THEN COMBINING SAID HEART CUT FRACTION WITH SAID RAFFINATE PHASE WHEREBY A SOLVENT OF IMPROVED ODOR AND SOLVENCY VALUE IS OBTAINED, SAID HEART CUT FRACTION AND SAID RAFFINATE PHASE BEING SWEETENED AFTER SEPARATION AND RECOVERY OF SAID HEART CUT FRACTION FROM SAID SOLVENT-FREE EXTRACT BY DISTILLATION. 